Association between metabolic syndrome, cognitive dysfunctions, and peripheral inflammation in schizophrenia

Introduction Metabolic syndrome (MetS) is of primary clinical interest because of its harmful impact on the general health and quality of life of patients with psychotic disorders. Paradoxically, MetS is associated with impaired cognitive functions in patients receiving antipsychotics primarily shown to improve cognition (e.g., clozapine and olanzapine). Objectives In this study, we aimed to investigate the relationship between MetS, cognitive functions, and peripheral inflammation. Methods The participants were 154 patients with schizophrenia. Fifty-seven patients met the criteria of MetS. We evaluated cognitive functions with the Repeated Battery for the Assessment of Neuropsychological Status (RBANS). The Positive and Negative Syndrome Scale (PANSS) quantified the clinical symptoms. We also measured the plasma levels of IL-6 and C-reactive protein (CRP). In addition to conventional statistics, we also calculated Cohen’s effect size (d) and Bayes Factors (BF10). Results Results revealed that patients with MetS exhibited worse cognitive function relative to patients without Mets in attention (d = 0.19, BF10 = 2.3) and delayed memory (d = 0.25, BF10 = 5.7). No significant between-group differences existed in immediate memory, visuospatial functions, and language. The MetS and non-MetS groups did not differ in positive, negative, or general symptoms. Higher IL-6 levels were associated with worse delayed memory (r=-0.56, BF10=34.6). Conclusions Our results suggest that MetS-associated cognitive dysfunctions are less severe than reported in the literature: it was confined to two cognitive domains, the effect size was small, and the Bayesian evidence level was weak. Peripheral inflammation may mediate the association between MetS and long-term memory dysfunctions. Disclosure of Interest None Declared